In general, comparing to lab experiments, field tests in OFC network often introduce more noise due to complex environmental fluctuation and crosstalk from adjacent classical fiber communication. The condition becomes even more challenging for TF-QKD, which requires optical phase stability for single photon level interference. For example, in the lab, a vibration due to human voice or walk will influence the optical phase and decrease the interference visibility [1]}. While, in the field, the human voice or activity can't be forbidden like in the lab. Considering these challenges, putting the experiment to a field test is not only necessary to prove its feasibility, but also an important step to explore the possibilities of the future global QKD networks.
